These filter elements can be manufactured by extrusion, in which context a ceramic material is pressed through an extrusion tool so that a prismatic body having a plurality of flow channels arranged in mutually parallel fashion is created. The extrusion operation is followed by a firing or sintering operation.
Both cordierite and silicon carbide can be used for the known filter elements. A difference between these two materials is that the thermal expansion of cordierite is substantially less than the thermal expansion of silicon carbide. For this reason, filter elements manufactured from silicon carbide are not produced “en bloc,” i.e. as a monolith, but instead are assembled from multiple filter segments. Each filter element encompasses a subset of mutually parallel flow channels. These filter segments form subunits (“bricks”) that are manufactured individually and then assembled into a filter element using a ceramic adhesive bonding agent.